Loader with self-leveling carrier



s. R. WALSTROM 2,731,162

LOADER WITH SELF-LEVELING CARRIER 3 Sheets-Sheet 2 INVENTOR 3mm a! A Munro v QM V Jan. 17,. 1956 Filed Nov. 19, 1953 fl F F E 1 E- 1 5:

447m may:

LOADER WITH SELF-LEVELING CARRIER Stanley R. Walstrom, Minneapolis, Minn., assignor to Superior Separator Company, Hopkins, Minn a corporation of Delaware Application November 19, 1953, Serial No. 393,169

Claims. (Cl. 214-140) This invention relates generally to improvements in material loading and handling equipment, and more particularly to certain improvements in the positioning of the actual load carrier, or fork as it is often called.

Basically the loader, with which my invention is associated, is quite similar to that disclosed in the Schwan Patent No. 2,295,917, issued September 15, 1942, and has in common therewith the fact that the loader includes a frame, generally mounted upon a tractor of any commonly available type, to which vertically swingable frame parts are pivoted at their rear ends and hydraulically adjusted to swing upwardly and downwardly at their forward ends. The load carrier, whether it be a fork, bucket or other device, is then pivotally or tiltably connected to the forward ends of these frame parts so that in action a loadmay be picked up from the ground, elevated and dumped and many other similar operations carried out. For properly handling the various loads it is necessary that the load carrier be tilted with respect to the frame parts by which it is raised and lowered and for this purpose there is conventionally provided a fluid motor or ram, which may be controlled by a valve, to tilt the load carrier upwardly and downwardly. It is found, however, that as the carrier moves upwardly and downwardly it is necessary that there be provision for What is referred to as a self-leveling action in order to keep the carrier from tilting rearwardly or forwardly to discharge a part or all of its load. In actuality the carrier is not usually leveled but is tilted rearwardly, as it moves upwardly, to better prevent the escape of the material as will be readily appreciated.

It is the primary object of my invention to provide an improved tilting or leveling system for such load carriers which is automatic in its operation to the extent that the carrier will be leveled or tilted, as may be necessary, as it moves upward and downward, but which is further manually controlled so that the carrier may be tilted through a far wider range for properly manipulating and dumping its load. Another object of my invention is to provide a load carrier adjusting mechanism for this purpose, including cooperating fluid motors or rams which are so connected that, as one motor is adjusted by the upwardly and downwardly moving frame parts, it has a compensating effect by means of a fluid displacement action upon the other fluid motor in order to control the tilt of the load carrier. There is also a tie-in to the hydraulic system between these two motors so that the operator may at any time manually control the tilt of the carrier.

A further object of my invention is to provide load carrier tilting mechanism of simple and practical construction and which includes, as one aspect, the provision of means for effectively multiplying or augmenting the tilting action of the carrier so that it may be moved through the desired wide amplitude of tilting movemerit, with relatively minor travel of the parts connected to tilt the carrier.

These and other more detailed and specific objects will be disclosed in the course of the following specification,

reference being had to the accompanying drawings, in which- Fig. 1 is a side elevation, partially in section, showing a tractor mounted loader of the general type disclosed in the Schwan patent aforesaid, although wtih later refinements, and illustrating one embodiment of my invention applied thereto.

Fig. 2 is an enlarged and fragmentary sectional view of the upper part of the loader of Fig. 1, better showing the tilting mechanism for the carrier.

Fig. 3 is a still further enlarged cross sectional detail along the line 3-3 in Fig. 2.

Fig. 4 is a side elevation of another and similar type of loader but particularly designed for use in connection with.

a slightly different type of tractor.

Fig. 5 is a side elevation and schematic diagram of the:

tilting mechanism of the loader of Fig. 4.

adjacent side of the load carrier.

Referring now more particularly and by reference: characters to the drawing, I have shown in Figs. 1 and 2. thereof an embodiment of my invention as associated! with a loader mechanism, designated generally at A, which, is supported by one ordinary type of tractor B having close= spaced steerable front wheels C and relatively widespreadl rear traction wheels D. The loader, per se, includes a main frame E suitably secured to the tractor B and therefore wheel supported for travel, in addition to which the ordinary hydraulic supply system, with which most tractors are now provided, is utilized for providing a source of fluid under pressure for operation of the various loader parts, or an entirely separate supply system may be used. It is, of course, to be understood that the main frame E of the loader may be of any desired construction for suitable attachment to the tractor and as here shown the frame includes an erect rear portion 10 at each side of which there are upper and lower pivots 11 and 12, and suitable forward bracing 13 from the upper part of the frame to the forepart of the tractor. At each side of the tractor there are arranged a pair of vertically swingable frame parts, designated generally at 14 and 15, which are respectively pivoted at their rear ends to the pivots 1211 so that the forward ends of these frame parts, which project forwardly beyond the tractor, may swing upwardly and downwardly with respect to the ground. Also forming part of the loader is a load carrier, designated generally at 16, and the same is mounted upon a transverse horizontal pivot axis 17 at the forepart of the loader frame assembly so that a load may be engaged and elevated or lowered, as may be necessary, the pivot connection of the load carrier permitting the same also to be tilted in a vertical plane for holding or dumping its contents.

In common with the teaching of the Schwan patent previously identified the swingable frame part 15 at each side of the tractor is an elongated reciprocated fluid motor or ram made up of a cylinder 18 within which there is a piston connected to a plunger 19. It is the rear end of the cylinder 18 which is attached to the pivot 11 at each side While the forwardly extending end of the plunger 19 is pivoted on a horizontal transverse axis at 20 to a suitable bracket or clip adjacent the forward end of the other swingable frame part 14. The latter then acts as a radius member so that the extension of the plunger 19 will perforce move the load carrier 16 in an upward direction, in an are centered about the pivot axis 12. The frame part 14 is therefore longitudinally rigid and as here shown comprises a formed-up box section member 21 which provides the necessary rigidity while also being hollow for the accommodation in the'forward 22" comprises an elongated' cylinder 23 the forward end of .which.is.pinned rat. 24.within the memberZl and within which cylinder there is a piston 25 having a rearwardly extending plunger 26. The fluid motor 22 constitutes atilting ram; the'purpose'of whichis to tilttheload carrier 16 about its pivot 17, and for this purpose there is attached'to the" rear endof the plunger 25-an elongated flexible element, such-as a cable 27, the'oppositeend of which is attached at 28 to the upper part'of the back 29-of tl1eload carrier 16: For convenience the load carier is here shown as being simply a fork having forwardly extending tines, one of which appears at 34), suitably securedat 31 to'the lower edge ofthe back 29although it is to be understood that the'load carrier'may be a bucket or any other suitable deviceaccording to the work to be done. Between its ends the cable'2-7 extends rearwardly from'its point ofattachment to the plunger 26 within the hollow member21 to apoint'adjacent the rear extremity thereof at which there is located a pulley 32 upwardly around whichthe cable is trained and then directed forwardly to its-connection at28 to'the load carrier.

The foregoing arrangement is obviously such that the introduction of fluid under pressure to the rear end of the cylinder 18, as through a fluid line 33, will project the plunger 19 forwardly to swing the load carrier in an upward direction, while as fluid is permitted to return through'the line 33 theweight will'cause the load carrier to descend by gravity. Likewise the introduction of fluid under pressure to the rear'end of the cylinder 23, as-through the-fluid line '34 connected'thereto, will project the plunger 26 in a forward direction exerting a pull upon the cable 27 so as to swing the load carrier 16 about its pivots 17 to tilt itsforward portion in an upward direction, where as when fluid is permitted to escape through the line 34 the weight of the load will tilt the load carrier in the opposite direction. Thus both of the fiuidmotors 15-22 are of the single-action variety, although it is to be understood that where desirable they may bearranged to operate as double-action rams without" departing from the scope of my invention. The precise details of the manner in which fluid is thus supplied for the operation of these fluid motors are also immaterial, but I have illustrated a manually controllable valve 35 as mounted upon a horizontal brace 36 of the frame E convenientto the operators station on the tractor B so that fluid may be selectively'supplied to the parts as required. It is also to be understood that while I have herein'iliustrated only the one side of the loader that it, of'course, has two sides and the parts may be duplicated throughout or, if desired, only the one tilting motor or ram 22'may be employed and the cable 27 at the opposite side of' the machine suitably operated by a cross connection from the pulley 32, or otherwise.

Asjwill be. understood by those skilled in the art it is desirable that the load carrier 16 be maintained at a certain level as to its'tines'3t), or that the tines actually be tilted upwardly somewhat as the load carrier is elevated" with a load, in order to properly holdthe load in place. Obviously" the relationship between the various parts and their pivots is such that this requires a compensating movement of the cables 27 where attached to the-upper'part of the load;carrier and a continuous tilting effect on the carrier. It is for this purpose ofcompensatingly adjusting the tilt of the load carrier that my invention is directed and the same comprises a thirdfluid motor, again of the reciprocating variety, which is designated generally at 37, including a comparatively short cylinder 38 within which there is a piston having a plunger 39. The cylinder 33 is pivotallyattached at its lower end at 40 to any. convenient adjacent'part of the upright frame portionltl while, the. plunger, 39 is pivotallyv attachedat 41 to. the, radius member. 21 at a point forwardly, thereonwithrespect;.to the pivot 12. As a result,.when the loadcarrier 16 is elevated; the leverage effective on this third or compensating fluid motor 37 is such as to withdraw the plunger 39-fromthe-cylinder 38 and vice-versa. The aforesaid fluid line 34 connected to the rear end of fluid motor 22 is then connected also directly at 42 to the lower end of the cylinder 38 and a suitable connection through line 43 is made to the valve 35. The entire system is, of course, fluid filled throughout and it will now be apparent that as the load carrier 16 moves upwardly, and the plunger 39 is withdrawn from the cylinder 38, the volume of fluidin the latter will increase with an effect on the motor 22rasua-result of which the plunger 26 is continuously repositioned in order to maintain the proper level or backward tilt of the load carrier 16. Thus self leveling of the carrier iseffected by fluid displacement, as between the cylinders 23 and 38, in a simple and very effective manner while at the same time the connection 43 to valve 35 will permit the total volume of fluid in these cylinders to be varied at any time for manually controlling the tilt of theloa'd carrier. Is is also to be understood'that the relative diameters of the cylinders'involved, as 'well asthe distance" between the pivots 12 and41, will be so preselected that the necessary self-leveling action will be carried out properly throughout all positions of the load'carrier;

In Figs. 4, 5 and 6 I have illustrated a modifiedven' sion of what is generically the same type of loaderbut particularly designed for use in connection with a different type of row crop tractor F having widespread front wheels, one of which appears at G, carried at the downturned endsof an arched axle H so" that high clearance is provided for row crops. The tractor, of

course, also has the usual rear traction wheels, one.of"

which appears at I, and all the wheels are usuallyad justable for various row crop spacing. The elevation of the arched front axle H is such that-in this case the.

upper radius member or swingable frame part of. the

loader, designated at 44, at each side of the tractor is formed with a reverse gooseneck or downwardly and then forwardly turned end, as seen at 44a, in order. to

clear. Otherwise insofar as the loader, per se; is concernedthe arrangement is very'similar to that previously described, there being an upright rear frame assembly 45' suitably secured to the tractor and braced at each side by a' forwardly and downwardly angling brace 46, with the frame provided with upper and lower pivots 47 and 48'for the attachment of the aforesaid member 44 and of the lower swingable frame member 49 at each side. Here also the latter member 49'is an elongated reciprocating fluid motor made up of a cylinder 50 pivoted at its rear end at 43 and a forwardly extending plunger 51 pivotally attached at 52'to the member 44 a short distance rearwardly of the end 44a. Again there is provided a valve 53 so that fluid may be selectively supplied to the rear end of each cylinder 50, as through a line 54, in order to raise the fore-ends of these swingable frame members, as fluid'is admitted to the cylinders, and lower said fore ends as'fluid is permitted to flow back out of the cylinders.

As here shown the load'carrier, designated generally at 55, of whatever variety it may be, is not pivoted at its side directly to the extremity of the forward endof the member 44 but instead is pivoted at'56' at each side rearwardly of the pivot of. an actuating'plate 57'of which the forward end is pivoted'at 58" to the extremity of member-44. At each side clearance is provided for the pivot 56 of the carrier where it projects through the plate 57 by the provision therein of an-arcuate slot 59 centered about the axis of pivot 58; Connection isthen made between the plate 57 and the adjacentside 60 of the load? carrier 55 by means of a pivot block 61-..pivotally pinned at 62 to thecarrier andxslidablyyarrangedin. a second The=-pl ate 57 as.- here shown tapers both forwardly and rearwardly inz.

and rectangular. slot'63 in the plate.

order. to accommodate slot 59 and -theerear extremity of the plate ateach side is then-pivoted-at -64-to. a trans.-

versely extending cross bar or truss 65 extending from one side of the assembly to the other. The cross bar 65 has a pivot pin 66 to which there is attached the lower end of a plunger 67 which has a piston slidable in a cylinder 68 forming part of a reciprocating fluid motor, designated generally at 69, for tilting the load carrier. This tilting ram 69, as it may be called, is located rearwardly of and in a generally upright position behind the load carrier 55 and the upper end of the cylinder 68 is pivoted at 70 to a suitable bracket 71 attached to the swingable frame member 44.

The foregoing arrangement is obviously such that the admission of fluid under pressure to the upper end of the cylinder 68 will downwardly project the plunger 67 and swing the plate 57 about its pivotal attachment 58 to the member 54 in a clockwise direction, as viewed in Fig. 4, and that the admission of fluid to the lower end of the cylinder 68 will, oppositely adjust these parts. They are shown in Fig. 4 as moved to the extreme of their travel by admission of fluid to the upper end of the cylinder 68, but when fluid is admitted to the lower end of that cylinder the plate 57, on swinging in a counterclockwise direction, will carry the pivots 6162 in an upward direction to swing the load carrier 55 about its pivot 56 so that the front edge of the carrier will be caused to move downwardly. While the plate 57 is moved on a lever arm as measured between the pivots 58 and 64 the load carrier 55 is moved on a lever arm measured from pivots 56 to 62, with the result that for a given travel of the plate 57 by ram 69 the load carrier will be caused to be tilted through a relatively larger angular increment. This is desirable as well known in the art in order to provide for the maximum dumping angle of the load carrier. The block 61 slides in slot 63 to provide the necessary play during this operation.

Fluid is supplied as aforesaid to upper and lower ends of cylinder 68 through fluid lines 72 and 73, respectively, which extend rearwardly toward the control station of the tractor. At their rearward ends the lines 7273 are crossed and respectively connected to the lower and upper ends of a reciprocating fluid motor, designated generally at 74, constituting the compensating motor or ram analogous to that shown at 37 in Figs. 1 and 2. Here also the ram 74 comprises a cylinder 75 pivoted at its lower end at 76 to the frame 45 with an upwardly extending plunger 77 pivoted at 78 to the member 44 forward of the pivot 47. Both the motors or rams 69 and 74 are in this case double-acting, but the same selfleveling action is obtained upon the load carrier 55 by the compensating displacement of fluid between the respective cylinders 68 and 75. Thus as the load carrier 55 is elevated fluid will be displaced from the upper end of cylinder 75 as the plunger 77 is withdrawn and this fluid will flow through the line 73 to the lower end of cylinder 68 to maintain the load carrier at the desired level and properly retain its load in place. Likewise as the load carrier is lowered the displaced fluid will flow through line 72 to again maintain the desired level of the carrier. In any case the valve 53 may also be manipulated to add fluid selectively to the lines 72-73 for manually adjusting the tilt of the carrier by the connection between the valve and said lines of feeder lines designated collectively at 79.

Fig. 5, in addition to illustrating the elements previously described, also for convenience schematically illustrates a pump 80 and reservoir 81 with the connections therebetween of lines 82 leading to the valve 53. It is believed, however, that the operation of the system will be clearly apparent Without details as to the valve structure.

It is understood that suitable modifications may be made in the structure as disclosed, provided such modifications come within the spirit and scope of the appended claims. Having now therefore fully illustrated and described my invention, what I claim to be new and desire to protect by Letters Patent is:

1. In a loader, a wheel borne frame having upper and lower pivots, a longitudinally arranged telescopic boom pivoted at its rear end to the iower pivot for up and down swinging movements at its forward end, a radius member similarly pivoted at its rear end to the upper pivot, means pivotally connecting the forward end portions of the boom and radius member, a load carrier pivoted for tilting movements on the forward end of the boom and radius member assembly, means for extending the boom to swing the load carrier upwardly, a hydraulic cylinder and a plunger and means connecting the latter to tilt the load carrier, means for supplying fluid to the cylinder for actuating the plunger and tilting the carrier, and another hydraulic cylinder and plunger connected between the frame and the said radius member and operative in response to upward and downward movement of the radius member for varying the volume of fluid in the cylinder which tilts the load carrier independently of said fluid supply.

2. In a loader, a wheel borne frame having upper and lower pivots, a longitudinally arranged telescopic boom pivoted at its rear end to the lower pivot for up and down swinging movements at its forward end, a radius member similarly pivoted at its rear end to the upper pivot, means pivotally connecting the forward end portions of the boom and radius member, a load carrier pivoted for tilting movements on the forward end of the boom and radius member assembly, means for extending the boom to swing the load carrier upwardly, a hydraulic cylinder and a plunger and means connecting the said cylinder and plunger between the radius member and load carrier to tilt the load carrier, means for supplying fluid to the cylinder for actuating the plunger and tilting the carrier, another cylinder and plunger and the same being connected between the radius member and frame for reciprocation as the load carrier is raised and lowered, and a fluid filled connection between the cylinders.

3. In a loader, a wheel borne frame having upper and lower pivots, a longitudinally arranged telescopic boom pivoted at its rear end to the lower pivot for up and down swinging movements at its forward end, a radius member similarly pivoted at its rear end to the upper pivot, means pivotally connecting the forward end portions of the boom and radius member, a load carrier pivoted for tilting movements on the forward end of the boom and radius member assembly, means for extending the boom to swing the load carrier upwardly, a hydraulic cylinder and a plunger and means connecting the said cylinder and plunger between the radius member and load carrier to tilt the load carrier, means for supplying fluid to the cylinder for actuating the plunger and tilting the carrier, another cylinder and plunger and the same being connected between the radius member and frame for reciprocation as the load carrier is raised and lowered, and a fluid filled connection between the cylinders, the pivot between the said other cylinder and radius member being so spaced from the said upper pivot that the reciprocation of the cylinder and plunger by the radius member will compensatingly tilt the load carrier with a self-leveling effect.

4. A loader having a wheel borne frame and vertically swingable frame parts connected thereto, a pair of actuating plates hinged at one end to the frame parts, a hydraulic tilting ram connected to the other ends of the plates for swinging them up and down about their pivots, a load carrier pivoted through the plates to the swingable frame members and said plates having arcuate slots to clear these pivots, slidable pivot blocks carried by the plates and pivoted to the load carrier to swing the same up and down on corresponding movements of the plates but on a shorter lever arm than the plates are operated, and fluid supply means for the tilting ram.

5. A loader having a wheel borne frame and vertically swingable frame parts connected thereto, a pair of actuating plates hinged at one end to the frame parts, a

hydraulic tiltingramconnected to'the OthGD ends of the platesiforl swingingithem .up and downabout theirpivots, a loadicarrierrpivotedthrough the plates to vthe-swingable frame rnembers and said plates having arcuate= slots to clear these pivots, slidablepivot blocks carried by the plates and pivoted to the load carrier to swing the sameup and down on corresponding movements'of the plates but on a shorter lever arm than the plates are operated, fluid supply means for the tilting ram, and means operapendently of the fluid supply means for leveling the carrier.

ReferencesCited-in the file of thispatent UNITED STATES PATENTS French Aug. 21, 1951 Stanley Oct. 14, 1952 

